In Sanaa on Tuesday, the presidential palace was overrun
by Shiite Houthi rebels, a situation the country's minister of information described as the "completion of a coup."
That's a problem for the United States, which has relied on the government in Yemen as an ally in battling the al Qaeda affiliate that's based there. A power vacuum could benefit al Qaeda in the Arabian Peninsula (AQAP), the terrorist offshoot that U.S. officials consider the most dangerous branch of the global jihadi network.
Obama himself cited the U.S.-Yemen partnership when he announced in September he was going after ISIS terrorists in Iraq and Syria.
Explaining why he was ruling out sending American troops to fight ISIS, Obama said he was modeling his strategy after what he said were successful efforts in Yemen and Somalia to partner with governments to go after terrorists.
"This strategy of taking out terrorists who threaten us, while supporting partners on the front lines, is one that we have successfully pursued in Yemen and Somalia for years," Obama said on September 10. "It is consistent with the approach I outlined earlier this year: to use force against anyone who threatens America's core interests, but to mobilize partners wherever possible to address broader challenges to international order."
What that strategy relied on, however, was a strong partnership between the United States and the existing government in Yemen, led by President Abdu Rabu Mansour Hadi. Hadi reorganized Yemen's military to better go after AQAP, a strategy that worked for a time. But the plan was waylaid when resources were diverted to battle the militant Houthis, a Shiite group who say they feel marginalized in the majority Sunni country.
Republicans have seized upon the latest news from Yemen to illustrate their opposition to Obama's terrorism strategy.
Sen. John McCain, now the chairman of the Senate Armed Services Committee, tweeted
"The 'success story' of Yemen continues to unfold" on Tuesday, followed by a link to a news report about the violence there.
When pressed by CNN in September whether U.S. efforts in Yemen could be described as a "success," the White House said the strategy there has worked.
Yemen is "a place where the American counterterrorism strategy that has been put in place by President Obama has succeeded in degrading the threat that those organizations pose to the United States," press secretary Josh Earnest said. "We intend to implement an analogous strategy against ISIL."
During Tuesday's State of the Union, Obama will "talk broadly about our counterterrorism strategy as part of our national security strategy, and as part of our way to make sure American principles are held up throughout the world," according to White House spokesman Eric Schultz.
A senior administration official said Obama was being updated on the situation in Yemen by his national security team.
"We strongly condemn the violence and those stoking it in an effort to disrupt Yemen's political transition. We will continue to support efforts to bring about a peaceful solution," the official said.